This invention relates generally to dosimeters of the type which may be carried by persons who may be exposed to radiation hazards and more particularly to a dosimeter sensitive to neutron and gamma radiation and being of the type that have built into them a quartz fiber electroscope.
It is a primary object of the present invention to provide a tactical dosimeter which is adapted to provide a person, for example a troop commander, with data about the current radiological status of his troops during the conduct of a battle in which tactical nuclear weapons are used.
Dosimeters of the type that are carried by persons who may be exposed to radiation, e.g. X-ray or gamma ray radiation, typically are comprised of a low power microscope which is mounted rigidly in a tube so that it is in focused relationship with a movable central portion of a quartz fiber which is covered with a platinum coating so as to render it conductive. The fiber is attached to a wire frame so that it is in an inverted U-shaped position. A portion of the wire frame is roughly parallel with the fiber, so that when fiber and frame are charged, the fiber is repelled from the frame and attached to the adjacent grounded wall of the tube in which the microscope and fiber support frame are mount. As a result, the fiber is caused to move across the field of view of the microscope as the potential of the quartz fiber support frame is varied.
U.S. Pat. No. 2,648,777 issued to O. G. Landsverk is illustrative of such a device. In addition to the means already noted, such devices include means in the support frame in order to charge the fiber negatively, whereupon the fiber is repelled from the frame. Subsequent to charging, a given radiation dosage causes ionization to occur in the surrounding medium adjacent the fiber whereupon the electrometer becomes partially discharged. The amount of movement the fiber has undergone during the discharge is indicted by the position of the fiber image on a reticle, thus providing a reading of the accumulated dosage to which the device has been exposed since the last charging process of the electroscope.